NZTD - The New Zealand Trait Database for shallow-water marine benthic invertebrates

Macrobenthic traits, for example feeding mode, life history, morphology, are increasingly used for determining responses of macrobenthic fauna to environmental change and influences on ecosystem functioning. Yet, trait information is scarce or non-existent in several parts of the world, such as New Zealand. This deficit makes collecting trait data a difficult and time-consuming task, limiting its potential use in trait-based assessments. Here, we present the New Zealand Trait Database (NZTD) for marine benthic invertebrates, the first comprehensive assessment of macrobenthic traits in New Zealand. The NZTD provides trait information for more than 700 macrobenthic taxa, categorised by 18 traits and 77 trait modalities. The NZTD includes five freely downloadable datasets, (1) the macrobenthic trait dataset, with outcomes from a fuzzy coding procedure, (2) the trait source information, (3) the references by taxa, (4) the full references list, and (5) the full taxa list used in the NZTD. Establishing the NZTD closes the trait knowledge gap in New Zealand and facilitates future research applying trait-based approaches to New Zealand’s coastal macrofauna.


Background & Summary
Traits are properties of organisms that can be measured, usually at the individual organism level and used comparatively across species [1][2][3] . Traits are generally assigned based on feeding mode, life history, morphology, physiology, and behavioural characteristics of species [4][5][6] . In recent decades, the use of trait-based analyses has expanded, advancing our understanding of marine ecosystem functioning 3,7-9 and how organisms are responding to environmental change (e.g. environmental gradients, anthropogenic disturbances, and climate change) 3,6,10,11 .
One challenge in applying trait-based approaches is the lack of knowledge and availability of species trait information. Macrobenthic fauna, defined as organisms retained on 0.5 mm mesh size, usually include large numbers of invertebrate taxa (e.g., polychaetes, crustaceans and molluscs), many of which are rare, small, cryptic, and inadequately studied. Therefore, gathering trait information from the literature or biological collections can be difficult and time-consuming 3,6,12,13 . Worldwide, several efforts have been made to alleviate the lack of macrobenthic trait information, for example establishing trait databases for the Arctic 14 , Southern Australia 13 , and Northwest Europe 12 , in addition to well-established online databases (e.g. MArLIN 15 , WoRMS 16 ), and taxa-specific trait databases (e.g. Polytraits 17 ). Despite these efforts, information about traits of macrobenthic fauna in several regions around the World is scarce or non-existent 3 , limiting the use of trait-based assessments that could assist conservation and management actions and increase understanding of the functioning of benthic ecosystems in those regions.
This article presents the New Zealand Trait Database (NZTD), aiming to (i) close knowledge gaps on macrobenthic trait information, and (ii) advance trait-based approaches for New Zealand. The NZTD is an open access database that followed the structure and traits presented in previous research 7,13,14 for easy comparability and sharing among researchers. The NZTD provides trait information for more than 700 taxa. This is the first comprehensive assessment focusing on traits of marine macrobenthic fauna of New Zealand. Our aim was to provide a reliable source of macrobenthic trait information and facilitate further research using trait-based perspectives in New Zealand marine waters.

Selection of traits.
The traits presented in the NZTD were selected based on a published global review 3 describing their relevance for the assessment of ecosystem functioning and identified as the most commonly used traits for assessing macrobenthic fauna 3 . Our selection also considered traits that could be compared across studies and geographical areas, i.e., are applicable to most benthic assemblages 6,7,13 . In total, 18 traits and 77 trait www.nature.com/scientificdata www.nature.com/scientificdata/ modalities allocated across four different subject areas (e.g. biology, habitat, life-history and larval type) 13 were assessed (Tables 1-4).
Trait allocation. Trait information was retrieved from different published primary literature (e.g., peer reviewed journal articles, books, thesis), secondary literature (e.g. online resources, reports), and expert knowledge (see full trait source database 34 ), depending on the availability of information for each taxon. We categorised the sources of the trait information into four categories based on origin: (1) New Zealand literature, (2) Australian literature, (3) Overseas literature, and (4) Expert knowledge/Online resources. We followed the approach used in the South Australian Trait Database 13 and allocated the trait information based on the available information for each taxon. When trait information of a particular taxon was missing, trait information from the closest  www.nature.com/scientificdata www.nature.com/scientificdata/ phylogenetic taxon was used. For example, if no trait information was available at Species level, trait information was used from another species within the same Genus; if information was unavailable at Genus level, we considered information at Family level. Additional considerations such as taxa distribution, resemblance, and expert judgment were also applied.
Trait expression. A fuzzy coding procedure was applied to describe trait expression, scoring each of the taxa analysed depending on the affinity that a taxon displayed with a trait-modality 13,35-37 . Our fuzzy coding used a scoring range from 0-1, with 0 being no affinity and 1 being high affinity to a trait. For example, coding the trait 'Feeding mode' for Amalda novaezelandiae (Gastropoda), considered that A. novaezelandiae is a predatory species, however it also exhibits scavenger feeding, giving a fuzzy coding of 0.5 as predator, and 0.5 as scavenger, completing the full allocation of 1 for the feeding mode trait.

Larval Larval type
Pelagic -planktotrophic Larval type and feeding mode.
Food source, ability of species dispersal, influence in nutrient cycling. 6    Taxa included. In total, we provide trait information for 702 taxa 18 . Different levels of taxonomic identification were assessed, 225 at Species level, 254 at Genus level, 139 at Family level, and the remaining 28 taxa at higher levels (Order, Class, or Phyla; Fig. 2a). The phylum with most records was Mollusca (244 records, 35% of all taxa), www.nature.com/scientificdata www.nature.com/scientificdata/ followed by Annelida (224 records, 32% of all taxa) and Arthropoda (178 records, 25% of all taxa), with the remaining 8% of taxa belonging to 15 different phyla (Fig. 2b).
Trait sources. Trait information was retrieved from several sources and a database containing this information was created for easy interpretation and useability 34 . Including all the traits assessed, 90% of the information was retrieved from primary and secondary sources, which included 45% from New Zealand literature, 39% from Australian literature and 7% from overseas literature. The remaining 9% of information was obtained from reputable resources online and expert knowledge 34 . Yet, we found that the source of trait information differed between types of traits (Fig. 3a). Across taxonomic levels, most of the trait information retrieved was available at the Family (41%), Genus (30%), and Species (21%) levels, with proportionally less at the Order/Class levels (6%; Fig. 3b). It was also evident that the traits larval type, life span, reproductive frequency and technique are less studied for the New Zealand macrobenthic fauna. www.nature.com/scientificdata www.nature.com/scientificdata/

technical Validation
The New Zealand Trait Database (NZTD) is based on macrobenthic fauna datasets previously validated, used, and published in different articles (e.g. 19-33 ,) and official reports, in which macrobenthic fauna were used to understand ecosystem functioning and to evaluate responses to environmental change.
Trait information was compiled using the same approach as for the SAMT database 13 , i.e., the NZTD retrieved information from the most reliable sources available with an accompanying dataset presenting all the references used for each taxon (trait references by taxa 40 ; full references list 41 ). In addition, the NZTD delivered a detailed dataset showing the taxonomic resolution of the trait information used for each taxa 34 .

Usage Notes
The New Zealand Trait Database (NZTD) can be freely viewed and downloaded from the repository Figshare 38 and NIWA website 39 . The information allocated on the Figshare repository is a static version of the data last reviewed on July 2023, further updates will be released in the same Figshare project, but the DOI could be different. A report record will be also included to control further updates. Yet, the datasets available on the NIWA website are dynamically updated.
The NZTD is an ongoing project, with continuous updates and refinements as additional taxa and trait information becomes available. Future updated releases will be published in the same host repositories 38,39 , seeking to keep the structure of NZTD as simple as possible, avoiding complexity, redundancy, and duplication between traits as it expands to include more taxa and traits. As the NZTD evolves, we strongly suggest users to approach the database with awareness of its limitations of available taxonomic and trait-based information, ongoing changes to taxonomic nomenclature, trait information, and trait classification. Future developments may also include an expanded trait database encompassing New Zealand and Australian macrobenthic fauna.

code availability
This research did not use or generate any coding to present the data described in the manuscript.